The present invention relates to an electronic board as a device for inputting information into a computer, to a coordinate input system, and to a coordinate input pen used therewith employing an infrared (hereinafter, simply referred to as xe2x80x9cIRxe2x80x9d) detection system.
An electronic board is one type of devices for inputting information into a computer. Specifically, the electronic board recognizes the location or the path on the board pointed or traced by a coordinate input pen as coordinate data, based on which a display image is output from a computer and projected onto the electronic board (screen) with a front or a rear projector.
There are various electronic board systems such as an electromagnetic induction system, a laser scan system, an ultrasonic system, a pressure sensitive system and the like. According to the electromagnetic induction system, a position of a coordinate input pen is detected by sensing wires wired throughout an electronic board which detects ac (alternating current) magnetic field generated by the coordinate input pen. The laser scanning system refers to a method in which a position of a coordinate input pen is detected with IR beams scanning parallel to a surface of a board, or to a method in which two laser scanners are employed to scan a path traced with a coordinate input pen. According to the ultrasonic system, an ultrasonic pulse is oscillated by a coordinate input pen. Then, the position of the coordinate input pen is calculated based on the time lags between the actual oscillation of the ultrasonic pulse and the detection of the oscillated ultrasonic pulse by ultrasonic sensors peripherally placed around the board. According to the pressure sensitive system, a position pressed by a coordinate input pen is detected with a pressure sensitive element provided over the entire surface of the board.
Except for the laser scanning system, the above-described systems have the following problems. The electromagnetic induction system or the pressure sensitive system cannot be used with a transparent electronic board, and a large-sized electronic board incorporating these systems would be unpractical and cost mindless to produce. The pressure sensitive system does not recognize signals corresponding to those of mouse buttons (e.g., double-click and right-click signals). The ultrasonic system is limited in accuracy and is easily affected by noise.
According to the laser scanning system, two laterally provided (i.e., at right and left) laser scanners scan over a large-sized display such as a screen to acquire the position of the coordinate input pen based on light reflected off the pen. Specifically, a reflective face of the tip portion of the pen reflects the lateral laser beams. The reflected beams are then sensed and processed by the two laser scanners, thereby determining the position of the pen. Alternatively, the tip portion of the coordinate input pen is equipped with an optical sensor which directly processes the acquired beam signals to determine the position of the pen. However, according to such structures, distortion or deformation of the display panel (or the screen), a tilt of the pen upon use, or the like may interfere with accurate reflection or receiving of the laser beams. As a result, the path of the pen may not always be accurately reproduced on the display panel (or the screen).
With regard to the above-described problems, the object of the present invention is to provide a coordinate input system and a coordinate input pen employing an IR detection system, which allow steady detection of the position of the pen even under the circumstances where a display panel is distorted or deformed, or where the coordinate input pen is tilted. The present invention also aims at providing an electronic board and an electronic board system for steadily displaying the path of the coordinate input pen.
Thus, instead of employing a system where two IR scanning beams that reflected off the coordinate input pen are detected or where light is directly detected with a light-receiving element provided at the tip portion of the coordinate input pen, the present invention employs a system where IR scanning beams scatter and perpendicularly propagate within a coordinate input pen to be detected. In order to ensure the detection of the IR scanning beams, a conical IR scattering member is provided at the end of the coordinate input pen. This scattering member only detects beams that are scattered generally perpendicular to the incident direction of the beam, i.e., beams that propagates along the axis of the pen. This detecting portion of the coordinate input pen is made longer along the axis of the pen so as to allow the detection of the incident beam even if there is distortion of a display panel (e.g., a screen), tilt of the coordinate input pen, or the like, thereby enabling accurate reproduction of the path of the coordinate input pen. A part or the whole tip portion of the pen may be made to light up in response to an IR scanning beam detection signal so that the user will always know the status of IR beam detection by the coordinate input pen, rendering the pen more manageable.
In one aspect of the invention, a coordinate input pen specifies and outputs coordinates of the pen by detecting two IR beams that are emitted from two separate positions for pivotally scanning over a plane parallel to a surface of a display panel. The coordinate input pen includes: a shaft portion; a transparent conical light scattering member with a rough surface placed at the end of the shaft portion; and a light receiving element for detecting an IR beam scattered within the light scattering member. The coordinate input pen of the invention is capable of outputting coordinates even when the tip of the pen is not touching the electronic board, as long as the tip is close enough to the board to cross with the two IR scanning beams.
Preferably, the shaft portion is provided with a displaying member which visually displays the status of receiving the IR beam. This displaying member may be used to visualize the status of receiving the IR beam as either normal (where the coordinate input pen is alternately receiving the two IR scanning beams) or abnormal (where only one of the two IR scanning beams is continuously being received).
According to another embodiment, the coordinate input pen may be provided with functions of producing signals corresponding to left click, right click and double click of a mouse or signals corresponding to an enter key of a keyboard of a personal computer (hereinafter, simply referred to as a xe2x80x9cPCxe2x80x9d). This may be realized, for example, by providing the shaft portion of the pen with buttons having functions corresponding to such mouse buttons or such keys.
According to still another embodiment of the invention, the coordinate input pen may include a writing tool for leaving a path written on the display panel while outputting coordinates of the pen. The writing tool may be, for example, a water marker, a chalk, a pencil, or a crayon.
The coordinate input pen of the invention may be used as a coordinate input device of an electronic board employing an IR detection system. In this case, the system is designed such that signals indicating beam rotation angles of two rotary mirrors that are separately provided in the electronic board and a beam detection signal from the coordinate input pen are transmitted to a signal controller of the electronic board either wirelessly or via a wire. The signal controller processes these signals to determine the position of the coordinate input pen and renders a path of the pen to be displayed on a display panel (e.g., a screen).
In another aspect of the invention, a coordinate input system includes: a first IR scanning beam generator and a second IR scanning beam generator which alternately generate IR scanning beams; a first reference sensor for generating a first reference signal upon detecting an IR scanning beam generated by the first IR scanning beam generator; a second reference sensor for generating a second reference signal upon detecting an IR scanning beam generated by the second IR scanning beam generator; the coordinate input pen which generates a first detection signal upon detecting the first IR scanning beam from the first IR scanning beam generator, and generates a second detection signal upon detecting the second IR scanning beam from the second IR scanning beam generator; and a signal controller for receiving the first reference signal from the first reference sensor, the second reference signal from the second reference sensor and the first and the second detection signals from the coordinate input pen, thereby outputting a position coordinates signal indicating coordinates of the coordinate input pen.
The signal controller may receive the detection signals from the pen either wirelessly or via a wire. The signal controller determines an angle made by a line linking the first IR scanning beam generator and the first reference sensor with a line linking the first IR scanning beam generator and the coordinate input pen, based on the time lag between the detection of the first reference signal and that of the first detection signal. The signal controller also determines an angle made by a line linking the second IR scanning beam generator and the second reference sensor with a line linking the second IR scanning beam generator and the coordinate input pen, based on the time lag between the detection of the second reference signal and that of the second detection signal. Based on the thus-obtained two angles and the distance between the first IR scanning beam generator and the second IR scanning beam generator, the coordinates of the coordinate input pen is calculated.
In still another aspect of the invention, an electronic board of the invention includes: a display panel; first and second IR scanning beam generators which are separately placed at the periphery of the display panel and which alternately generate IR scanning beams which rotate parallel to the surface of the display panel; a first reference sensor placed at the periphery of the display panel, for generating a first reference signal upon detecting an IR scanning beam generated by the first IR scanning beam generator; a second reference sensor placed at the periphery of the display panel, for generating a second reference signal upon detecting an IR scanning beam generated by the second IR scanning beam generator; the coordinate input pen which generates a first detection signal upon detecting the first IR scanning beam from the first IR scanning beam generator, and generates a second detection signal upon detecting the second IR scanning beam from the second IR scanning beam generator; and a signal controller for receiving the first reference signal from the first reference sensor, the second reference signal from the second reference sensor, and the first and second detection signals from the coordinate input pen, thereby outputting a position coordinates signal indicating coordinates of the coordinate input pen.
An electronic board system is realized which is capable of displaying a path on the display panel traced by the coordinate input pen as if the input pen has actually drawn the path on the display panel. Such electronic board system includes: the electronic board; a computer for receiving a position coordinates signal from the signal controller of the electronic board; and an image displaying means connected to the computer for displaying a mark on the display panel at a position assigned by the position coordinates signal indicating the coordinates of the coordinate input pen. The display panel may be of any kind such as a rear-projector-type screen, a front-projector-type screen, a plasma display, a flat CRT (cathode-ray tube), or generally used whiteboard or blackboard. When a whiteboard or blackboard without an image displaying function is employed, a projector such as a rear projector or a front projector may be employed as an image displaying means for displaying a mark. A plasma display or a flat CRT with an image displaying function may serve both as a display panel and an image displaying means.
Where a coordinate input pen is integrated with a writing tool such as a water marker or a chalk, there are provided, along a side of a whiteboard or a blackboard, a pair of IR scanning beam generators for generating IR scanning beams for pivotal scanning, and a pair of reference sensors for detecting the IR scanning beams at fixed positions. By providing a signal controller which receives a coordinate input signal from the pen and outputs the coordinates of the pen, data such as characters or graphics written or drawn on the whiteboard or blackboard with the water marker or chalk (i.e., a path of the writing tool) can be easily incorporated into a computer or the like as information of consecutive coordinates. Such coordinate input pen is preferably provided with buttons or the like for determining the beginning and the end of the coordinates of the path to be incorporated.
This and other advantages of the present invention will become apparent to those skilled-in the art upon reading and understanding the following detailed description with reference to the accompanying figures.
This specification includes part or all of the contents as disclosed in the specification and/or drawings of Japanese Patent Application No. 11-92918 which is a priority document of the present invention.